Process function

A process or operation size is a physical quantity that occurs only at state changes and is path dependent in the sequence. It is therefore important for the process variables, in which way a state to another state. This is in contrast to the state variables, which depend only different from the process variables on the current condition, and for which there is no significance to the way in which this state is reached.

By supply or removal of energy undergoes a thermodynamic system a change of state. This process is only possible during a process. The work done in this case W and exchanged heat Q are therefore process variables.

• Thermodynamic process